568 



MOLLUSCA 



PHYLUM VI 



Family 6. Acteocinidae, novum (Tornatimdae Fischer). 



Radula unarmed. Tertiary and Recent. 



Adeocina Gray {Tornatina Adams) (Fig. 1065). Cylindrical, with projecting 

 spire, and sinistral, tilted j)rotoconch. Columella bearing a single 

 fold. Tertiary and Recent. 



Retnsa Brown. Shell resembling Cyliclma. Tertiary and 

 Recent. 



Volvula Adams {Vohulella Newton). 

 Fusiform, the body whorl forming a point 

 above the spire. Eocene to Recent. 



Fk:. 1064. 



Bnllaria am-piiUa 

 (Linn.). Pliocene ; Asti, 

 Italy. 



Fig. 1065. 



Actcocina exerta 

 (Desli.). Oligocene ; 

 JeiiiTPs, near Btampe.s 

 (after Uesliayes). 



Family 7. Scaphandridae Fischer. 



Spire concealed ; radula with few teeth in a 

 row. Trias to Recent. 



Scaphander Montf. (Fig. 1066). Shell sub-cylindrical, with epidermis, usually 

 spirally striated. Body whorl of enormous capacity, much dilated 

 anteriorly. Columella sx)iral, leaving a false umbilicus. Creta- 

 ceous to Recent. 



Atys Montf. Cretaceous to Recent. Diaphana Brown. Ter- 

 tiary and Recent. Smaragclinella Adams. Recent. 



Cylichna Loven {Bullinella Newton) (Fig. 1067). Small, 

 cylindrical, solid ; spire deeply perforated at 

 the .«ummit ; body whorl covering all the 

 others. Aperture very narrow, outer margin 

 lower than the axis of the shell. Columella 

 thickened anteriorly and bearing a small plica- 

 tion ; often umbilicated. Trias to Recent. 



Fk;. 1066. 



Scujihaiuler coniciLs 

 Desli. Eocene ; Brack- 

 lesliam, England. 



Family 8. Philinidae Fischer. ^'"- ^°'^'- 



Cyliclina conoidra 



Similar to Scaphandridae., but shell internal, welnhehn, neai^A^izey.' 



loosely coiled, pnmctate. Cretaceous to Recent. 

 Philine Ascan. {Bullaea Lam.) (Fig. 1068). Cretaceous to Recent. 



Family 9. Umbraculidae Pilsbry. 



Shell limpet-shaped, with low sub-central apex, and sharp, thin edges. Tertiary and 

 Recent. 



Umbracidum Schum. {Umbrella Lam.). Shell orbicular, broad, 

 patelliform, ornamented exteriorly with concentric lines of growth ; 

 internal surface with concentrically undulating striae. Eocene to 

 Recent. 



Other families of Tectibranchiata, such as Aplysiidae, Pleuro- 



branchidae, etc., aie rej)resented in the Recent fauna, but their thin, 



I'hiihie pxcavata often membranous shells have not been found fossil. The suj^posed 



CalVamr" Gross^er''; Aphjsias I'eported from the Pliocene by Pliilippi are flakes from the 



Gri-non, near Paris.' interior of Pelecypod valves. 



